1. Field of the Invention
The present invention relates, generally, to electronic systems and methods. Particularly, the invention relates to an apparatus and method of detecting an object or the lack of the presence of an object. More particularly, the invention relates to a device and method of high speed detection of the presence or lack of an object via pulse amplitude differential measurement. The invention is particularly useful in medical/pharmaceutical dispensing systems, automated manufacturing and production systems, food processing systems, commercial and industrial food service systems, packaging systems, and a variety of other commercial, industrial, municipal and residential systems, for sensing the presence, absence or flow of objects or material.
2. Background Information
The state of the art includes various systems that utilize one or more optical or other sensors in their operations for detecting objects.
Methods or apparatus which attempt to reject, limit or otherwise avoid noise in optical sensor systems are disclosed, in general, in the following United States patents: Skell et al., U.S. Pat. No. 5,744,793; Skell et al., U.S. Pat. No. 5,550,369; Skell et al., U.S. Pat. No. 5,491,333; Grozinger et al., U.S. Pat. No. 5,250,801; Schiller, U.S. Pat. No. 5,245,177; Kim, U.S. Pat. No. 4,973,834; Hatten et al, U.S. Pat. No. 4,282,430; Hösel, U.S. Pat. No. 5,002,102; Fukuyama et al., U.S. Pat. No. 4,306,147; Devale, U.S. Pat. No. 4,437,499; and Upton, U.S. Pat. No. 4,202,387. Known portion control apparatus and methods for dispensing systems are shown in the following United States patents: Upton, U.S. Pat. No. 4,202,387 and Skell et al., U.S. Pat. No. 5,744,793.
This technology is believed to have limitations and shortcomings, including vulnerability to noise or error caused by dirty, scaled or otherwise fully or partially blocked transmitters or sensors, weak transmitters or sensors, fluctuations in temperature, resistance or capacitance, or ambient sunlight or interior lighting. For this and other reasons, a need exists for the present invention.
The invention provides a system, apparatus and method which are believed to fulfil the need and to constitute an improvement over the background technology.
Applicants' assignee is the owner of the following US patents and US patent applications: Olson et al., U.S. Pat. No. 5,902,998 entitled Apparatus and Method for Detecting an Object Using Digitally Encoded Optical Signals, issued May 11, 1999; Olson et al., U.S. Pat. No. 6,265,709 B1 entitled Apparatus and Method for Detecting an Object Using Digitally Encoded Optical Data, issued Jul. 24, 2001, Olson et al., application Ser. No. 09/419,547 entitled Detection Apparatus and Method Using Digitally Encoded Serial Data, filed Oct. 18, 1999; and Berghoff et al., application Ser. No. 09/691,366 entitled Automatic Portion Control Using Strain Gauge Technology, filed Oct. 18, 2000.
All US patents and patent applications, and all other published documents mentioned anywhere in this application are incorporated by reference in their entirety.